Volatile amines such as dimethyl aminoethanol, ethyl aminoethanol, isopropyl aminoethanol, 2-dimethylamino-2-methyl propanol, 2-amino-2-methyl propanol, and others, as well as ammonia, have for many years been used for neutralizing and solubilizing water-dilutable, lacquer binders. Whereas ammonia evaporates to a considerable extent from such aqueous lacquer systems at room temperature, so that the lacquers thicken and eventually coagulate, the above-mentioned amono alcohols are relatively non-volatile at room temperature since their vapor pressure at 20.degree. C. is only from about 1 to 5 torr. They therefore ensure good stability of the lacquers in storage.
At higher temperatures, in particular at the baking or stoving temperatures of from about 120.degree. to 175.degree. C. normally employed for lacquers dried in an oven, the aforesaid amines evaporate more or less completely from the lacquer films at temperatures in the range of about 135.degree. to 165.degree. C., depending on the boiling points of the amines, and enter the atmosphere.
Since new lacquer systems requiring progressively smaller proportions of auxiliary solvents have been developed in recent years and the first completely solvent-free aqueous lacquers have already been tested, the use of volatile amines would appear to be particularly unsatisfactory in that they pollute the atmosphere.
In spite of this well known disadvantage, the volatility of the neutralizing agent has hitherto been demanded as an essential precondition for good film quality. Sensitivity to water, a tendency to re-emulsify, insufficient gloss, yellowing, and disturbances in the flow of the lacquers are frequently attributed to insufficient volatility of the amine used.